Forging presses are already well-known in the art, such as, for example, in RU 2 016 692.
Standard four-die forging units are in particular equipped with four actuators, typically including respective independent drives that in turn enable radial movement of the respective dies for forging with a motion that runs simultaneously perpendicular thereto by all four dies in one uniform tangential direction. The disadvantage of these types of four-die pressing units lies in the independence of the drive means for each die of the forging unit, since this then requires the four dies to be synchronized, thereby significantly complicating the construction of the four-die forging units. If the moment has not been determined with sufficient precision at which the four dies simultaneously contact the workpiece to be forged, it is possible for critical flattened areas and/or cracks to appear in this workpiece.
These disadvantages can be prevented by the four-die forging unit disclosed in RU 2 018 404 C1 that includes a pressure plate and a retaining plate having oblique surfaces on which retainers and four dies kinematically connected to the retainers are mounted, the dies being attached to and guided in the guides of the retainers in such a way that they can move in a transverse direction relative to the retainers. As a result, the dies are mounted in an X-configuration and can thus be displaced obliquely, that is, at an angle relative to the horizontal and vertical center planes when the pressure plate is displaced relative to the retaining plate. The retainers for the dies here are connected to each other kinematically through a box-shaped frame and have the ability to move within guide grooves therein. A fixed stop is attached to each retainer on one of its identically oriented lateral surfaces. The fixed stops interact with the laterals surfaces of the dies mounted on adjacent retainers when the four-die forging unit is in use. Each die is forced back to the starting position by an elastic element.
Publication EP 2 014 390 B1 also describes a similar four-die forging unit that is designed in an X-configuration with the object of achieving an extended repair-free service life due to the modified design.